A method, referred to in the art as "hot riveting", is known for fixing an electrical connector to a printed circuit board. The hot riveting method involves the use of a connector housing comprising a housing body made of plastic and a plastic peg (leg) downwardly extending from the lower surface of the housing body. To fix the connector to the circuit board, the peg is inserted through a peg insertion bore in the printed circuit board until the lower surface of the housing body lies flat on the board surface. Then, the distal end of the peg, which protrudes from the insertion bore on the opposite side of the circuit board, is contacted with a mold taking surface of a heated mold pushing rod so as to melt and deform the peg. The mold taking surface of the mold pushing rod has a spherical recess with a greater diameter than that of the insertion bore in the board. As a result, the distal end of the peg is spherically deformed to a diameter greater than that of the insertion hole, thereby fixing the connector to the board.
Unfortunately, however, the peg does not always deform to the predetermined spherical shape of the mold taking surface due to the nonuniformity of heat conduction from the mold pushing rod to the peg or due to the nonuniformity, etc., of the inner mechanical properties of the peg resulting from the nonuniform hardness of the resin inside the peg. In such cases, the housing-to-board connection force becomes unstable, thus posing a reliability problem.
Additionally, with the prior art hot riveting method, it is often necessary to design or adjust the dimension of the peg in accordance with different insertion hole diameters in the board. The melting means, such as the mold pushing rod, must also be adjusted. Therefore, the manufacturing and mounting operations become more complex.
An object of the present invention is to provide an electrical connector which can readily and positively be fixed to a board, such as a printed circuit board, and can eliminate the necessity of providing any melting means, such as a mold pushing rod.
It is also another object of the present invention to provided an electrical connector which requires less design restriction to the peg and requires no adjustment of the peg.